Table. Studies in which errors of content were found in the references.

Study	References checked (n)	Incorrect referencing*1 (%)	Journals examined (n)
Wager, Middleton 2008, Cochrane Review (2)	3836	20, range: 0 to 50	74 (various specialties)
Reddy et al. 2008 (3)	258	7.8, range: 3.5 to 10.3	Surgery (4)
Al-Benna et al. 2009 (6)	117	13.7, 95% CI: 8.6–19.5	Burns (2)
Singh, Chaudhary 2009 (7)	46	43.5, 95% CI: 29.2–57.8	Dermatology (1)
Davis et al. 2010 (8)	200	38, 95% CI: 30.1–47	Orthopedics (4)
Awrey et al. 2011 (5)	900	18.5, range: 10.5 to 22.0	Surgery (5)
Authors‘ own pilot study *2	50	Major errors: 18, 95% CI: 9.2–30.5; minor errors: 14, 95% CI: 6.3–25.7	Medicine, general (Deutsches Ärzteblatt)

The study by Wager and Middleton is a systematic review (Cochrane) analyzing publications up until the end of 2007. In order not to include any publication twice, the studies listed below Wager and Middleton include only articles published from 2008 onwards.

^*1 Reference does not support statement made in the article, or only partially supports it.

^{* 2} The pilot study did not analyze references to books.

Agreement between the two evaluators (authors) was satisfactory (weighted Cohen‘s ? = 0.583)